Drain the lychee and cut into pieces, reserving the syrup.
Drain the pandan jelly and cut into cubes.
Drain the jackfruit, reserving the syrup if desired.
Drain the coconut jelly.
In a large bowl, combine pandan jelly, jackfruit, coconut jelly, and lychee pieces.
Pour in the lychee syrup and, optionally, some jackfruit syrup.
Add coconut milk and milk (or half-and-half).
Taste and add condensed milk if more sweetness is desired.
Refrigerate Che Thai for at least 1–2 hours.
Serve cold with ice cubes in a glass or cup.